This invention relates to connector apparatus which enables precision location of two parts relative to each other by the action of a single locking force, and is releasable to allow immediate impedance-free separation of the parts when the locking force is removed.
Among the most common problems encountered in engineering are the fixing of an item in a desired position and the release of a fixed item when it must be moved.
The joints needed for these tasks must have specific properties, but frequently the designs used possess awkward characteristics which can only be overcome by means of human dexterity and ingenuity at the time of fixing or release. This indicates that some of the properties of the joints are not those required.
By the use of appropriate measures the basic requirement that the item is under control at all times can be met while the need for human intervention, which is only a product of the design, can be reduced or eliminated.
With the trend towards automation the joining and separation must be achieved entirely under the action of machinery. A system providing only the required properties, which is simple and reliable, is thus essential.
The major disadvantage of many existing designs is that they employ mechanisms which fail to create the correct conditions at the fixing or release of the object and which interfere when control must be transferred from one to the other. They possess properties which are not only unnecessary but which impede or prevent the desired operation. Additional mechanisms have to be provided to compensate for the incorrect fixing and the unwanted interaction, requiring extra features to provide compliance.
Many designs use pins or rails for guidance, but this introduces surfaces parallel to the direction of movement with the friction problems this entails due to the sliding which must occur between the components of the joint. Where high lateral positioning accuracy is needed with separability, there is a conflict between the two functions: for the positioning the clearances between pin and hole need to be very small, but for separation they need to be large to allow the passage of one relative to the other.
Where the joint location and load carrying parts are not the same, then there is a conflict between them which leads to loss of the required control during joining or separation, or to the need for additional components to deal with the problem.
Those designs using narrow conical tapered interfaces have potential problems with jamming, as they require close tolerances to achieve correct positioning and need additional locking sleeves and rotational constraints, which are themselves the source of more problems.
Many designs have locks which require complex motions to perform their tasks, and use locking systems which often interfere with the function of joining or separation.
Locking surfaces perpendicular to the direction of movement are often used, introducing friction problems to the locking and release operation. Here, also, tolerance requirements conflict between the positional and movement needs.
The choice of assembly direction is frequently prescribed by the design of the joint used, thus limiting the application of that particular design.
U.S. patent application Ser. No. 371,353 (Moses J.LONG/NASA) filed Apr. 23, 1982 and now abandoned describes a connector comprising male and female parts whose interfaces comprise a conical part and a separate sleeve for immobilizing the parts along the cone axis. Precise alignment of the sliding surface of the sleeve, between the male and female parts requires very tight tolerances for the cones ; when the two parts are correctly and tightly assembled, their separation can be difficult or impossible due to the risk of jamming. The parts wear inevitably and the connector becomes unusable relatively rapidly.